1. Field of the Invention
The present general inventive concept relates to a hard disk drive, and more particularly, to a method of writing data using a coercivity distribution of a data storage medium to the data storage medium.
2. Description of the Related Art
Hard disk drives are data storage devices adopted in computers, MP3 players, mobile phones, etc. In general, data is written to concentric tracks formed on disk surfaces of data storage medium loaded into hard disk drives. The data storage medium (disks) are installed at spindle motors to rotate at high speeds, and data is read or written by magnetic heads.
The disks are the data storage medium of the hard disk drives and include magnetic layers storing data using magnetic anisotropic characteristics. Coercivity of the disks, i.e., coercivity of the magnetic layers, are closely related to the reliability of data written to the disks. Coercivity means a strength of a magnetic field in which an inverse magnetic field is applied to a magnetized magnetic body, and thus magnetization of the magnetic body is “0. ” If a strength of the coercivity of the disks is large, a strong write magnetic field is required to write the data to the disks, but the preservation of the data is improved. If a strength of the coercivity of the disks is small, a weak write magnetic field is required to write the data to the disks, but the preservation of the data is deteriorated.
A strength of coercivity varies with temperature. As the temperature drops by 1° C., a strength Hc of coercivity of a disk is increased by 15 to 16 Oersteds (Oe). If the temperature rises, the strength Hc of the coercivity of the disk is decreased. Thus, if a write magnetic field optimized to write data at a room temperature is applied to write data to a disk having a temperature lower than the room temperature, the data is not written to the disk at a recognizable strength, i.e., weak write occurs. Also, if the write magnetic field optimized to write the data at the room temperature is applied to write data to a disk having a temperature higher than the room temperature, data is written to several tracks including an adjacent track, in which previously written data becomes erased. Thus, pre-written data is erased, i.e., adjacent track write (ATW) and adjacent track erase (ATE) occur. Such weak write and ATW (or ATE) increases a bit error rate (BER) and channel statistic measurement (CSM), and thus a data processing performance of a hard disk drive is deteriorated.